I agree with Jack, remove the manifold and install the turbo on a work bench. Those gaskets in the link provided look sweet.
You will have to shift your exhaust back about an inch for the new turbo and you'll have to shim your transmission dipstick about a 1/2" to clear the exhaust housing on the new turbo. On mine, I didn't have to clock the compressor housing, it was just fine. I also didn't adjust the wastegate before installation, I have enough adjustment in the boost elbow that goes into the compressor housing. If you're making too much boost just turn the set screw out in 1/4 turn increments until you reach the boost you want.
One very important thing to remember though and I'll make it in bold letters so you don't forget. Install the drain tube on the new turbo before it goes on the truck. When installing the drain tube use a light coat of RTV sealant on the drain tube gasket or it will leak oil and when you install it on the truck make sure the drain tube is fully inserted into the engine block.
When you have it all assembled look everything over and ensure all the bolt are tight.